package com.tys.algorithm.beginner;

// 测试链接：https://leetcode.com/problems/balanced-binary-tree

public class Code28_BalancedBinaryTree {
    public static class TreeNode {
        public int val;
        public TreeNode left;
        public TreeNode right;

        TreeNode(int val) {
            this.val = val;
        }
    }

    //1.整棵树是否平衡，2.整棵树的高度是多少
    public static class Info {
        public boolean isBalanced;
        public int height;

        public Info(boolean i, int h) {
            isBalanced = i;
            height = h;
        }
    }

    public static boolean isBalanced(TreeNode root) {
        return process(root).isBalanced;
    }

    public static Info process(TreeNode x) {
        if (x == null) {
            return new Info(true, 0);
        }

        //x!=null
        Info leftInfo = process(x.left);
        Info rightInfo = process(x.right);

        int height = Math.max(leftInfo.height, rightInfo.height) + 1;

        boolean isBalanced = leftInfo.isBalanced && rightInfo.isBalanced &&
                Math.abs(leftInfo.height - rightInfo.height) < 2;
        return new Info(isBalanced, height);
    }


}
